fit/.  >:  'S± 


Issued  January  18,  1913. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.— Bulletin  1-o. 

A.  D.  MELVIN,  Chief  of  Bureau. 


THE  INFLUENCE  OF  BREED  AND  INDIVIDUALITY  ON 
THE  COMPOSITION  AND  PRQffiffiES  OF  MILK. 


Missouri, 


C.  H. 

Professor  of  Dairy  Husbandry \ 
AND 

ROSCOE    H.  SHAW, 

Chemist,  Dairy  Division,  Bureau  of  Animal  Industry 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1913. 


Issued  January  18.  1913. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.— Bulletin  156. 

A.   D.   MELVIN,   Chief  of  Bureau. 


THE  INFLUENCE  OF  BREED  AND  INDIVIDUALITY  ON 
THE  COMPOSITION  AND  PROPERTIES  OF  MILK. 


BY 

C.  H.  ECKLES, 

Professor  of  Dairy  Husbandry,  University  of  Missouri, 

AND 
ROSCOE    H.  SHAW, 

Chemist,  Dairy  Division,  Bureau  of  Animal  Industry. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1913. 


BUREAU  OF  ANIMAL  INDUSTRY. 


Chief:  A.  D.  Melvin. 

Assistant  Chief:  A.  M.  Farrington. 

Chief  Clerk:  Charles  C.  Carroll. 

Animal  Husbandry  Division:  George  M.  Rommel,  chief. 

Biochemic  Division:  M.  Dorset,  chief. 

Dairy  Division:  B.  H.  Rawl,  chief. 

Field  Inspection  Division:  R.  A.  Ramsay,  chief. 

Meat  Inspection  Division:  Rice  P.  Steddom,  chief. 

Pathological  Division:  John  R.  Mohler,  chief. 

Quarantine  Division:  Richard  W.  Hickman,  chief. 

Zoological  Division:  B.  H.  Ransom,  chief. 

Experiment  Station:  E.  C.  Schroeder,  superintendent. 

Editor:  James  M.  Pickens. 

DAIRY  DIVISION. 

B.  H.  Rawl,  Chief. 

Helmer  Rabild,  in  charge  of  Dairy  Farming  Investigations. 
S.  C.  Thompson,  in  charge  of  Dairy  Manufacturing  Investigations. 
L.  A.  Rogers,  in  charge  of  Research  Laboratories. 
Ernest  Kelly,  in  charge  of  Market  Milk  Investigations. 
Robert  McAdam,  in  charge  of  Renovated  Butter  Inspection. 
2 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Bureau  of  Animal  Industry, 
Washington,  D.  C,  July  11,  1912. 
Sir:  I  have  the  honor  to  transmit,  and  to  recommend  for  publi- 
cation in  the  bulletin  series  of  this  bureau,  the  accompanying  manu- 
script entitled  "The  Influence  of  Breed  and  Individuality  on  the 
Composition  and  Properties  of  Milk,"  by  Messrs.  C.  H.  Eckles,  pro- 
fessor of  dairy  husbandry,  University  of  Missouri,  and  Roscoe  H. 
Shaw,  chemist  in  the  Dairy  Division  of  this  bureau. 

The  experimental  work  reported  herein  forms  part  of  a  series  of 
cooperative  investigations  inaugurated  in  1906  between  the  Dairy 
Division  and  the  Missouri  Agricultural  Experiment  Station,  with  the 
object  of  studying  in  detail  the  factors  influencing  the  composition 
and  properties  of  milk  as  produced  under  normal  dairy  conditions. 
The  first  results  of  the  work  have  been  forwarded  for  publication  as 
Bulletin  155,  entitled  "The  Influence  of  the  Stage  of  Lactation  upon 
the  Composition  and  Properties  of  Milk." 
Respectfully, 

A.  D.  Melvin, 
Chief  of  Bureau. 
Hon.  James  Wilson, 

Secretary  of  Agriculture. 

3 


CONTENTS. 

Page. 

Introduction 7 

Plan  of  the  investigation 8 

Method  of  sampling  and  preparation  of  samples  for  analysis 8 

The  true  average  per  cent 9 

Results  of  the  experiments 9 

Total  solids 10 

Fat 12 

Total  protein 14 

Casein 15 

Relation  of  the  casein  to  the  fat 16 

Sugar 18 

The  chemical  and  physical  constants  of  the  fat 19 

Relative  size  of  the  fat  globules 19 

The  Reichert-Meissl  number 21 

The  iodin  absorption  number 23 

The  saponification  or  Koettstorfer  number 24 

The  melting  point  of  the  fat 25 

Summarv  and  conclusions 26 


ILLUSTRATION. 


Fig  .  1 .   Relal  Lve  size  of  the  fat  globules  in  milk  of  dairy  cattle 20 


THE  INFLUENCE  OF  BREED  AND  INDIVIDUALITY  ON  THE  COM- 
POSITION AND  PROPERTIES  OF  MILK. 


INTRODUCTION. 

In  1906  the  Dairy  Division  of  the  Bureau  of  Animal  Industry,  in 
cooperation  with  the  Missouri  Agricultural  Experiment  Station, 
began  a  series  of  investigations,  the  main  object  of  which  was  to 
study  in  detail  the  factors  influencing  the  composition  and  proper- 
ties of  normal  milk.  It  is  a  well-known  fact  that  although  the 
same  constituents  are  always  present  in  milk,  the  relative  amount 
of  each  is  subject  to  constant  variations.  Among  the  causes  of 
these  variations  are  known  to  be  the  breed  of  ftie  animal,  the  stage 
of  lactation,  the  individuality,  and  to  some  extent  the  feed,  the 
interval  between  the  milkings,  and  the  temperature  and  weather 
conditions.  It  is  also  known  that  the  first  and  the  last  milk  drawn 
differ  in  composition. 

A  large  amount  of  data  has  been  published  regarding  these  varia- 
tions, the  greater  part  of  which  deals  with  the  fat  content  alone. 
In  planning  this  series  of  investigations  it  was  arranged  to  give 
attention  first  of  all  to  the  variations  occurring  during  the  period 
of  lactation.  The  data  concerning  this  part  of  the  subject  have 
been  prepared  for  publication  as  Bulletin  155  of  the  Bureau  of  Ani- 
mal Industry,  entitled  "The  Influence  of  the  Stage  of  Lactation  on 
the  Composition  and  Properties  of  Milk."  In  carrying  on  this  inves- 
tigation the  plans  were  so  arranged  that  the  influence  of  breed  and 
individuality  of  the  animals  could  be  studied  concurrently  with  that 
of  the  period  of  lactation,  and  a  presentation  of  these  results  is  the 
object  of  the  present  paper. 

There  is  no  lack  of  data  concerning  the  influence  of  the  breed  and 
the  individuality  of  the  animal  upon  the  composition  of  milk  as  far 
as  the  per  cent  of  the  fat  is  concerned,  although  in  practically  all 
investigations  reported  there  was  no  uniformity  in  the  rations  fed 
the  animals  and  no  data  taken  concerning  the  composition  of  the 
fat  produced.  When  the  influence  of  the  stage  of  lactation  is  not 
taken  into  account,  and  when  the  ration  is  changed  from  time  to 
time  or  varies  with  different  animals,  it  is  clearly  impossible  to  state 
54010°— Bull.  156—13 2  7 


8  INFLUENCE   OF  BREED  AND   INDIVIDUALITY   ON   MILK. 

to  what  extent  any  variation  found  may  be  due  to  the  ration  fed 
and  to  what  extent  to  the  stage  of  lactation,  breed,  or  individuality 
of  the  animal.  It  is  especially  important  to  keep  the  ration  uni- 
form, since  it  has  been  demonstrated  that  the  nature  of  the  food 
has  an  important  influence,  more  particularly  in  regard  to  the  com- 
position of  the  fat. 

PLAN  OF  THE  INVESTIGATION. 

Eleven  animals  were  selected  for  the  investigation,  consisting  of  3 
representatives  each  of  the  Jersey,  Holstein,  and  Shorthorn  breeds, 
and  2  of  the  Ayrshire  breed.  These  cows  were  typical  specimens 
of  the  breed — that  is  to  say,  neither  superior  nor  inferior  producers 
of  milk,  but  about  the  average.  They  were  all  purebred  and  reg- 
istered. They  were  kept  under  much  the  same  conditions  as  would 
be  found  in  a  commercial  dairy  except  in  regard  to  the  control  of 
the  feed  of  the  animals.  The  ration  fed  was  of  uniform  composi- 
tion throughout  the  entire  lactation  period  and  was  made  up  as 
follows : 

Choice  alfalfa  hay 3  parts. 

Grain  mixture: 

Corn,  8  parts 

Bran,  1  part 

Oats,  1  part 


2  parts. 


This  ration  supplied  the  nutrients  necessary  for  milk  production  in 
about  the  right  proportion.  The  ratio  between  the  hay  and  the 
grain  was  such  that  the  animals  would  eat  the  entire  ration  at  all 
times.  The  amount  fed  was  governed  by  the  needs  of  the  animal. 
The  animals  all  went  through  the  entire  lactation  period  with  no  ill 
effects  resulting  from  the  lack  of  variety,  and  in  no  case  was  there 
any  serious  sickness  of  any  kind.  The  hay,  which  was  the  most 
variable  part  of  the  ration,  was  bought  in  large  quantities  from  the 
same  source  in  order  that  there  might  be  few  changes  in  its  compo- 
sition. The  animals  were  housed  at  night  in  the  barn  for  feeding 
and  milking  and  in  the  daytime  were  turned  outside  in  a  dry  lot. 
The  date  for  beginning  the  taking  of  samples  was  5  days  after  the 
birth  of  the  calf.  The  sampling  was  continued  until  the  production 
of  milk  declined  to  the  point  where  in  a  commercial  dairy  the  cow 
would  not  be  milked  longer.  A  more  detailed  account  of  the  plan 
of  the  investigation  is  found  in  Bulletin  155,  previously  mentioned. 

METHOD    OF   SAMPLING   AND    PREPARATION    OF    SAMPLES    FOR 

ANALYSIS. 

The  milk  was  weighed  immediately  after  milking  and  mixed  by 
pouring  from  one  pail  to  another.  A  sample  consisting  of  about  1 
liter  placed  in  a  glass  jar  bearing  the  number  of  the  cow  and  marked 


RESULTS   OF    THE   EXPERIMENTS. 


9 


with  the  amount  of  milk  produced  was  delivered  at  the  laboratory. 
A  certain  number  of  cubic  centimeters  per  pound  of  milk  produced 
was  then  measured  out  and  placed  in  a  closed  receptacle.  In  this 
manner  a  composite  sample  was  prepared  representing  the  produc- 
tion of  that  particular  cow  for  1  week.  The  milk  was  preserved  by 
the  addition  of  formalin.  At  the  end  of  the  week  the  composite 
sample  was  thoroughly  mixed  and  a  subsample  consisting  of  about 
300  c.  c.  taken  for  analysis.  The  remainder  of  the  composite  sam- 
ple was  heated  to  the  proper  temperature  and  the  cream  separated 
with  a  hand-power  separator.  The  cream  so  obtained  was  churned 
by  shaking  in  a  glass  jar,  and  the  butter  resulting  was  melted  on  a 
steam  bath.  The  methods  of  sampling  and  analysis  have  been 
described  in  detail  in  Bulletin  155;  it  is  sufficient  to  say  that  the 
methods  of  analysis  followed  were  those  of  the  Association  of  Offi- 
cial Agricultural  Chemists  wherever  possible. 

THE  TRUE  AVERAGE  PER  CENT. 

In  many  cases  in  reporting  analyses  of  milk  a  simple  average 
instead  of  a  true  average  is  given.  An  average  made  in  this  man- 
ner is  often  misleading.  In  the  case  of  the  constituents  of  the  milk 
it  generally  gives  a  result  somewhat  high,  since  milk  becomes  richer 
as  it  decreases  in  amount  toward  the  end  of  the  lactation  period. 
Unless  otherwise  stated  the  averages  given  in  this  publication  rep- 
resent true  averages.  The  average  per  cent  of  fat  for  the  lactation 
period,  for  example,  is  found  by  dividing  the  total  milk  into  the 
total  fat  produced. 

RESULTS  OF  THE  EXPERIMENTS. 

Table  1  gives  the  data  concerning  the  cows  used  in  this  investi- 
gation. Under  the  heading  " Period  samples  were  taken"  is  shown 
the  periods  covered  by  the  samples  taken  for  analysis. 

Table  1. — Data  concerning  the  cows  used. 


! 

To- 

Av- 

To- 

Breed. 

No. 
of 

cow 

Age 

Date  of 

i      calving. 

Date  of 
breeding. 

Period  samples  were  taken. 

tal 

yield 

of 

erage 
fat 
con- 

tal 

yield 

of 

milk. 

tent,     fat. 

Ys.  mos. 

Lbs. 

P.ct.    Lbs. 

Jersey 

4 

6 

10 

Nov.  13,1906 

Dec.  30,1906 

Nov.  24, 1907,  to  Sept.  7, 1908. . . 

5.429 

4.  s7  264. 45 

Do 

99 

8 

1 

Jan.     1.1907 

Mar.  23.1907 

Jan.  5, 1907,  to  Nov.  30, 1907. . . . 

6.115 

4.64  284.04 

Do 

US 

11 

4 

Sept.  27. 1906 

Not  bred 

Oct.  6, 1906,  to  Oct.  26, 1907 

.-..  7-VA 

5. 36,307.  45 

Ayrshire. . 

300 

3 

8 

Dec.  28,1907 

Feb.  23,1908 

Dec.  29, 1907,  to  Oct.  3, 1908 

6,275 

3.51  220.34 

Do 

301 

4 

8 

Sept.  27, 1907 

Mar.  16.1908 

Sept.  29, 1907,  to  Sept.  18, 1908. . 

6,382 

3. 85  245. 64 

Holstein . . 

205 

5 

.3 

July  17,1907 

Dec.    1,1907 

Julv  20, 1907,  to  Aug.  8, 1908. . . . 

8.684 

3. 24  280.  76 

Do 

206 

5 

0 

May  31,1907 

Sept.  28. 1907 

June  1 ,  1907,  to  Apr.  4. 1908 

8.994 

2.93  263.66 

Do 

209 

3 

8 

Julv  20,1907 

Nov.  18, 1907 

July  20, 1907,  to  July  4, 1908 

8.814 

3.02  273.34 

Shorthorn 

400 

4 

4 

Sept.  30, 1907 

Jan.   25,1908 

Oct.  5, 1907,  to  Aug.  1, 1908 

5,172 

3.89  201.37 

Do 

402 

4 

11 

Oct.  13,1907 

Dec.  21.1907 

Oct.  19, 1907,  to  Julv  18, 1908. . . 

4.449 

4.13183.57 

Do 

403 

6 

0 

Feb.  11,1908 

July     7, 1908 

Feb.  15, 1908,  to  Dec.  19, 1908. . . 

6,539 

3.35  220.52 

10 


INFLUENCE   OF   BREED  AND   INDIVIDUALITY    ON   MILK. 


TOTAL    SOLIDS. 

The  determinations  for  total  solids  were  made  by  using  the  Bab- 
cock  asbestos  method.  The  figures  given  are  in  each  case  an  average 
of  the  determinations  for  4  weekly  composite  samples.  These  are 
simple  averages.  The  averages  given  for  the  lactation  period  of  the 
animal  and  for  the  breeds  are  true  averages. 

Table  2  gives  the  percentage  of  total  solids  for  each  of  the  11  ani- 
mals used  in  the  investigation  by  4-week  periods,  the  average  for 
each  animal  for  the  period  of  lactation,  and  the  average  by  breeds. 
The  results  correspond  closely  with  those  usually  given  for  the  breeds 
included.  In  Table  3  is  given  a  compilation  of  analyses  reported  by 
several  experiment  stations  in  this  country.  The  figures  used 
include  only  those  that  represent  purebred  animals  of  the  respective 
breeds,  and  where  an  entire  period  of  lactation  is  involved.  The 
data  included  in  the  column  headed  "  Other  American  experiment 
stations''  include  all  in  print  coming  under  the  above  conditions. 
A  portion  of  this  data  was  taken  presumably  by  calculation  from  the 
specific  gravity  and  the  fat.  Since  these  animals,  owned  by  various 
experiment  stations,  represent  a  variety  of  conditions,  it  is  believed 
that  the  average  figure  given,  which  includes  all  the  data  of  such 
kind  available  up  to  the  present,  is  reasonably  accurate. 

Table  4  gives  the  composition  of  the  total  solids  in  percentage  of 
fat,  protein,  and  sugar.  The  ash  is  not  included,  since  it  was  lacking 
in  some  of  the  data,  and  furthermore,  the  amount  of  ash  is  so  uniform 
with  the  different  breeds  and  different  individuals  that  no  marked 
variations  were  found.  The  animals  supplying  the  data  from  the 
New  Jersey  and  New  York  experiment  stations  are  the  same  as  in 
Table  3. 


Table  2. — Average  percentage  of  total  solids  for  each 

periods. 

cow,  and  breed  average,  by  4-week 

Jerseys. 

Ayrshires. 

Four-week  period  No. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1 

Per  cent. 
14.13 

Per  cent. 

Per  cent. 

Per  cent. 
14.13 
13.58 
13.92 
13.64 
13.60 
14.07 
14.02 
14.06 
13.76 
14.43 
14.88 
15.58 
16.10 
17.16 

Per  cent. 
13.07 
12.27 
12.14 
11.81 
11.66 
11.35 
11.38 
12.15 
12.56 
13.85 

Per  cent. 
13.20 
12.50 
12.57 
12.64 
13.09 
12.86 
12.63 
12.64 
12.49 
11.78 
13.55 
13.04 
13.27 

Per  cent. 
13.13 

2 

13.09 
13.30 
13.15 
12.92 

12.  76 
13.04 
12.81 

13.  35 
14.27 
15.15 
16.08 

14.08 
14.55 

12.39 

3 

12.36 

4 

14.14 
14.28 
14.15 
13.87 
13.77 
13.  63 
14.57 

12.23 

.-, 

12.38 

15.30 
15.16 
15.61 
14.79 
14.45 
14.42 
15.08 
16.10 
17.16 

12.11 

7 

12.01 

g 

12.39 

9... 

12.52 

10 

12.81 

11 

13.55 

12 

13.04 

13 

13.27 

14 

True  average  of  total  solids. 

14  09 

L3.34 

15.02 

14.09 

12.08 

12.71 

12.41 

RESULTS   OF    THE   EXPERIMENTS. 


11 


Table  2. — Average  percentage  of  total  solids  for  each  cou\  and  breed  average,  by  4-veek 

periods — Continued . 


Holsteius. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1 

Perct. 
11.74 
11.58 
11.70 
11.95 
12.11 
11.77 
11.98 
12.16 
11.95 
12.12 
12.20 
12.50 
13.04 
13.42 

Per  ct. 
10.95 
10.10 
10.18 
10.27 
10.54 
10.73 
10.75 
10.80 
11.01 
11.90 
13.30 

Per  ct. 
11.24 
10.23 
10.  63 
11.07 
11.15 
10.96 
11.20 
11.23 
11.58 
12.58 
12.99 
13.51 
14.52 

Per  cent. 
11.31 
10.  64 
10.84 
11.10 
11.27 
11.15 
11.31 
11.39 
11.51 
12.20 
12.83 
13.01 
13.  78 
13.42 

Per  ct. 
13.71 
13.29 
13.05 
12.48 
13.06 
13.05 
12.96 
13.08 
13.03 
12.43 
12.84 

Perct. 
13.74 
13.29 
13. 07 
13.07 
13.16 
12.97 
13.02 
12.93 
13.81 
13.94 

Per  ct. 
12.85 
12. 16 
11.75 
11.56 
11.56 
11.65 
12.77 
12.  52 
12.38 
12.90 
13.19 

Per  cent. 
13.  43 

2 

12.91 

3 

12.  62 

4... 

12. 37 

12.59 

6 

13.56 

7 

12.92 

8 

12.84 

9 

13.07 

10 

13.09 

11 

13. 02 

12 

13 

14 

True  average  of  total  solids. 

12.12 

10.73 

11.35 

11.38 

13.  OS 

13.01 

12.17 

12.69 

Table  3. — Comparison  of  total  solids  in  this  investigation    inth   results  reported  by 
American  experiment  stations. 


This  investiga- 
tion. 

New  Jersey  Ex- 
periment Sta- 
tion.1 

New  York  Ex- 
periment Sta- 
tion.2 

Other  American 
experiment  sta- 
tions. 

General  average. 

Breed. 

Num- 
ber of 
ani- 
mals. 

Average 
total 
solids. 

Num- 
ber of 
ani- 
mals. 

Average 
total 
solids. 

Num- 
ber of 
ani- 
mals. 

Average 
total 
solids. 

Num- 
ber of 
ani- 
mals. 

Average 
total 
solids. 

Num- 
ber of 
ani- 
mals. 

Average 
total 
solids. 

Jerseys 

Guernsevs. 

3 

Per  cent. 
14.09 

3 
3 
3 
3 
3 

Per  cent. 
14.34 
14.48 
12.70 
12.12 
12.45 

3 
2 
4 
2 

Per  cent. 
15.5 
14.8 
12.8 
12.2 

29 
6 

17 
9 

Per  cent. 
14.90 
14.20 
12.98 
12.29 

38 
11 

26 
17 

6 

Per  cent. 
14.70 
14.49 

Ayrshire . . 
Holstein  . . 
Shorthorns 

2 
3 
3 

12.41 
11.38 
12.69 

12.72 
12.00 
12.57 

1  Neilson,  James.    Experiments  with  different  breeds  of  dairy  cows.    New  Jersey  Agricultural  Experi- 
ment Station,  Bulletin  77.    New  Brunswick.  Dec,  1890. 

2  New  York  Agricultural  Experiment  Station.  Tenth,  Eleventh,  and  Twelfth  Annual  Reports.     Geneva, 
1891.  1892,  1S93. 

Table  4. — Average  composition  of  the  total  solids  in  milk  of  dairy  cattle,  as  reported  by 
American  experiment  stations. 


Breed. 


Jersey 

Guernsey. .. 

Ayrshire 

Holstein 

Shorthorn.. 


Fat. 


New 
Jer- 
sey. 


P.ct. 
33.3 
34.7 
29.1 
29.1 
29.3 


New 
York. 


Mis- 
souri. 


Aver- 


P.ct. 

P.ct. 

36.4 

35.1 

35.1 

27.3 

29.6 

28.0 

27.1 

29.4 

P.ct. 
34.9 
34.9 
28.7 
28.1 
29.3 


Protein. 


New 
Jer- 
sey. 


New 
York 


P.C. 

P.ct. 

27.6 

25.4 

27.1 

24.7 

27.4 

26.3 

27.1 

27.4 

26.3 

Mis- 
souri. 


P.ct. 
25.8 


26.1 
28.1 


P.ct. 
26.3 
25.9 
26.6 
27.5 
26.4 


Sugar. 


New 

Jer- 


New 
York. 


P.ct. 
33.8 
33.3 
38.1 
38.7 


P.ct. 
33.4 
35.0 
40.8 
39.1 


Mis- 
souri. 


Aver- 


P.ct. 
34.5 


37.3 
39.3 


P.ct. 
33.9 
34.2 
39.5 
38.4 
38.9 


The  fat  represents  from  28  to  35  per  cent  of  the  total  solids,  varying 
especially  with  the  breed  and  to  some  extent  with  the  individual. 
The  total  solids  produced  by  the  Jersey  and  Guernsey  breeds  contain, 


12 


INFLUENCE   OF  BREED  AND   INDIVIDUALITY   ON   MILK. 


on  an  average,  34.9  per  cent  of  fat,  which  is  relatively  high  as  com- 
pared with  the  Holstein,  Ayrshire,  or  Shorthorn  breeds.  Among  the 
breeds  included  in  these  data  the  Holstein,  with  an  average  of  28.1 
per  cent,  has  the  lowest  proportion  of  fat,  while  the  Shorthorn  ranks 
next.  The  rule  is  that  those  animals  having  a  higher  per  cent  of  fat 
in  the  milk  also  have  a  relatively  larger  proportion  of  fat  in  the  solids. 
The  individual  animals  show  some  variations,  but  on  the  whole  they 
follow  the  characteristics  of  their  breed  quite  closely.  The  per  cent 
of  fat  in  the  total  solids  produced  by  the  3  Jerseys  used  in  this  inves- 
tigation varied  from  34.6  to  35.7,  the  3  Holsteins  from  26.7  to  27.3, 
while  the  3  Shorthorns  varied  from  27.7  to  31.7.  The  individual 
variation  has  to  be  taken  into  account  in  connection  with  the  total 
solids,  but  is  of  less  importance  than  is  the  variation  due  to  breed. 

FAT. 

Table  5  gives  the  percentage  of  fat  in  the  milk  of  the  11  animals 
represented  in  the  investigation,  expressed  in  the  same  manner  as 
the  total  solids.  The  well-known  facts  regarding  the  relative  compo- 
sition of  the  milk  for  the  4  breeds  used  is  brought  out  in  these  data. 

Table  6  gives  the  average  percentage  of  fat  in  the  milk  of  animals 
used  in  investigations  at  the  New  Jersey  and  New  York  experiment 
stations;  also  a  compilation  showing  the  average  per  cent  of  fat  for 
all  registered  animals  of  the  respective  breeds,  the  records  of  which 
have  been  published  by  American  experiment  stations.  This  table 
includes  only  data  relating  to  purebred  animals  and  where  it  is  possi- 
ble to  obtain  a  true  average  per  cent  of  fat  for  the  entire  period  of 
lactation.  It  is  believed  that  the  summary,  representing  as  it  does  a 
large  number  of  animals  in  different  States  under  somewhat  compar- 
able conditions,  gives  a  reliable  average  as  to  the  fat  content  of  the 
milk  of  the  breeds  represented. 

Table  5. — Average  percentage  of  fat  for  each  cow,  and  breed  average,  by  4-week  periods. 


Jerseys. 

Ayrshires. 

Four-week  period  No. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1 

Per  cent. 
5.17 
4. 63 
5.07 
4.85 
4.81 
5.00 
4.73 
4.51 
4.73 
5.18 

Per  cent. 
5.22 
4.79 
4.43 
4.40 
4.33 
4.22 
4.  36 
4.18 
4.63 

4.  98 

5.  62 

6.  07 

Per  cent. 

Per  cent. 
5.20 
4.91 
5.02 
4.79 
4.88 
4.98 
4.93 
4.83 
4.84 
4.88 
5.23 
5.68 
5.48 
6.47 

Per  cent. 
4.01 
3.61 
3.38 
3.36 
3.32 
3.26 
3.30 
3.53 
3.74 
4.52 

Per  cent. 
3.87 
3.74 
3. 81 
3.81 
4.08 
3.78 
3.95 
3.94 
3.67 
3.58 
4.92 
3.96 
4.18 

Per  cent. 
3.97 

2 

5.31 
5.  55 
5.11 
5.51 
5.71 
5.69 
5.80 
5.17 
4.47 
4.83 
5.28 
5.48 
6.47 

3.68 

3 

3.60 

4 

3.59 

5 

3.70 

6 

3.52 

7 

3.63 

8 

3.74 

9 

3.71 

10 

4.05 

11 

4  92 

12 

3.96 

13 

4.18 

14 

True  average  of  total  fat.. 

4.87 

4.64 

5.36 

4.95 

3.51 

3.85 

3.68 

RESULTS   OF    THE   EXPERIMENTS. 


13 


Table  5. — Average  percentage  of  fat  for  each  cow,  and  breed  average,  by  4-week  periods — 

Continued. 


Holsteins. 

Shorthorns. 

Tour-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1  

P.ct. 
3.24 
3.14 
3.02 
3.25 
3.29 
3-06 
3.26 
3.25 
3.15 
3.31 
3.31 
3.49 
3.68 
3.68 

P.ct. 
3.07 

2.88 
2.58 
2.84 
2.89 
3.06 
2.88 
3.00 
3.00 
3.09 
3.40 

P.ct. 

3.12 
2.60 
2.74 
3.24 
3.14 
2.81 
2.94 
3.01 
3.01 
3.52 
3.46 
3.90 
5.28 

Per  cent. 
3.14 
2.87 
2.78 
3.11 
3.11 
2.96 
3.03 
3.09 
3.05 
3.31 
3.39 
3.69 
4.48 
3.68 

P.ct. 
4.12 
4.09 
3.99 
3.65 
3.70 
3.69 
3.85 
3.73 
4.05 
4.16 
4.17 

P.ct. 
4.55 
4.17 
3.97 
3.80 
3.84 
3.92 
3.98 
3.90 
4.67 
4.42 

P.ct. 
3.58 
3.38 
3.18 
3.16 
3.14 
3.13 
3.23 
3.55 
3.85 
4.00 
4.05 

Per  cent. 
4.08 

2...                  

3.88 

3...                     

3.71 

4...                          

3.54 

5  ..                         

3.56 

6  .                        

3.58 

7 

3.69 

8 

3.73 

9 

4.19 

10 

4.19 

11 

4.11 

12 

13.. 

14.. 

True  average  of  total  fat. . . 

3.23 

2.93 

3.10 

3.09 

3.89 

4.13 

3.37 

3.73 

Table  6. — Average  percentage  of  fat  in  milk  of  dairy  cattle,  as  reported  by  American 

experiment  stations. 


New  Jersey. 

New  York. 

Missouri. 

All  American  ex- 
periment stations. 

Breed. 

Number 

of 
animals. 

Average 
fat. 

Number 

of 
animals. 

Average 
fat. 

Number 

of 
animals. 

Average 
fat. 

Number 

of 
animals. 

Average 
fat. 

Jersey 

3 
3 
3 
3 
3 

Per  cent. 
4,78 
5.02 
3.68 
3.51 
3.65 

3 
2 

4 
2 

Per  cent. 
5.60 
5.15 
3.57 
3.28 

3 

Per  cent. 
4.#95 

153 
21 
24 
83 
40 
9 

Per  cent. 
5.14 

Guernsey 

4.98 

Ayrshire 

2 
3 
3 

3.68 
3.09 
3.73 

3.85 

Holstein 

3.45 

Shorthorn 

3.63 

Red  Poll 

4.03 

It  is  a  well-known  fact  that  individuals  within  a  breed  vary  consid- 
erably in  the  percentage  of  fat.  The  data  here  given  are  too  limited 
to  contribute  much  of  value  on  this  point.  While  by  far  the  greater 
number  of  individuals  within  the  breed  will  come  close  to  the  average 
for  that  breed,  a  comparatively  few  vary  widely.  It  is  characteristic 
of  the  breeds  having  the  higher  percentage  of  fat  to  show  the  greater 
individual  variations.  The  percentage  of  fat  secured  during  a  lacta- 
tion period  may  also  be  influenced  to  some  extent  by  the  time  of  the 
year  in  which  the  milking  period  began.1  On  the  averager  the  milk 
produced  during  the  fall  and  early  winter  has  a  higher  percentage  of 
fat  than  that  produced  by  the  same  animal  in  the  early  spring  and 
summer.  For  this  reason  the  cow  that  is  fresh  in  the  fall  and  pro- 
duces the  largest  quantity  of  milk  during  the  cool  weather  will  have 
a  higher  average  test  for  the  year  than  will  be  the  case  if  she  freshens 
in  the  spring  and  produces  the  maximum  yield  during  the  period  of 
warm  weather. 


1  Eckles,  C.  H.    Jahreszeitliche  Schwankungen  des  prozentischen  Fettgehaltes  in  Kuhmilk. 
wirtschaftliches  Zentralblatt,  vol.  5,  no.  11,  p.  488-502.    Leipzig,  Nov.  1909. 


Milch- 


14 


INFLUENCE  OF  BREED  AND  INDIVIDUALITY   ON   MILK. 


TOTAL    PROTEIN. 

Table  7  gives  the  percentage  of  total  nitrogen  as  protein  for  each 
individual  and  the  average  for  each  breed.  The  totals  are  also  cal- 
culated as  protein  by  using  the  factor  6.38.  The  results  show  a 
decided  influence  due  to  the  breed  of  the  animals,  the  Jersey  having 
a  uniformly  higher  percentage  of  protein  than  the  others.  The  Hol- 
steins  are  the  lowest,  while  the  Shorthorns  and  Ayrshires  range 
between  the  Holsteins  and  Jerseys.  The  marked  influence  exerted 
by  the  stage  of  lactation  upon  the  proportion  of  this  constitutent 
present  can  be  seen  from  the  data  given  and  has  been  shown  in  a 
previous  publication.1 

Table  8  is  a  compilation  from  the  same  sources  as  used  in  previous 
tables  showing  the  average  percentage  of  protein  in  the  milk  of  5 
breeds.  It  will  be  noted  that  the  figures  obtained  at  the  Missouri 
Experiment  Station  for  Holsteins,  Jerseys,  and  Ayrshires  are  some- 
what lower  than  those  obtained  at  the  New  Jersey  and  New  York 
stations,  while  the  figure  for  the  Shorthorns  is  slightly  above.  There 
is  some  variation  with  the  individuals  regarding  the  amount  of  this 
constituent  secreted,  as  is  the  case  with  other  constituents  of  the 
milk.  The  individuals  and  breeds  having  the  higher  percentage  of 
fat  have  at  the  same  time  the  higher  percentage  of  protein.  The 
same  animals  also  have  a  higher  ratio  of  fat  to  protein.  With  the 
11  cows  used  in  our  investigation,  for  each  pound  of  protein  there 
was  found  in  the  milk  of  the  Jerseys  1.36  pounds  of  fat,  in  the  Ayr- 
shires 1.13,  in  the  Shorthorns  1.10,  and  in  the  Holsteins  1.05.  While 
an  individual  or  a  breed  that  produces  milk  with  a  high  percentage 
of  fat  is  certain  to  have  a  high  percentage  of  protein  as  well,  the  pro- 
tein and  the  fat  do  not  increase  in  the  same  proportion. 

Table  7. — Average  total  nitrogen  for  each  cow,  and  breed  average,  by  4-week  periods,  and 
average  total  nitrogen  and  protein  for  the  whole  lactation  period. 


Four-week  period  No. 

Jerseys. 

Ayrshires. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1 

Per  cent. 
0.52 
.53 
.57 
.61 
.60 
.59 
.59 
.57 
.62 
.66 

Per  cent. 
0.51 
.51 
.51 
.49 
.49 
.49 
.48 
.50 
.52 
.56 
.62 
.66 

Per  cent. 

Per  cent. 
0.52 
.52 
.55 
.55 
.58 
.58 
.58 
.57 
.59 
.62 
.63 
.68 
.75 
.77 

Per  cent. 
0.53 
.47 
.48 
.47 
.46 
.47 
.46 
.49 
.57 
.67 

Per  cent. 
0.56 
.50 
.48 
.51 
.51 
.53 
.51 
.50 
.53 
.53 
.53 
.57 
.65 

Per  cent. 
0.54 

2 

0.51 
.56 
.54 
.65 
.65 
.67 
.64 
.64 
.64 
.65 
.70 
.75 
.77 

.48 

3 

.48 

4 

.49 

5 

.49 

6 

.50 

7 

.49 

8 

.50 

9 

.55 

10 

.60 

11 

.53 

12 

:i 

13 

J4.    ... 

True    average    of    total 

.58 
3.70 

.51 
3.27 

.62 
3.97 

.57 
3.64 

.49 
3.11 

.52 
3.33 

.51 

True    average    of    total 

3.25 

1  Bulletin  155,  Bureau  of  Animal  Industry,  U.  S.  Department  of  Agriculture.    Washington,  1912. 


RESULTS   OF   THE   EXPERIMENTS. 


15 


Table  7. — Average  total  nitrogen  for  each  cow,  and  breed  average,  by  4-week  periods,  and 
average  total  nitrogen  and  protein  for  the  vjhole  lactation  period — Continued. 


Four-week  period  No. 

Holsteins. 

Shorthorns. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Averaget 

for  Shotr- 

horns. 

1 

P.ct. 
0.49 
.43 
.44 
.44 
.45 
.45 
.45 
.44 
.48 
.48 
.51 
.55 
.59 
.65 

P.ct. 
0.44 
.38 
.37 
.39 
.42 
.42 
.41 
.43 
.44 
.51 
.71 

P.ct. 
0.50 
.45 
.45 
.47 
.45 
.46 
.50 
.49 
.52 
.60 
.65 
.73 
.71 

P.ct. 
0.48 
.42 
.42 

.43 
.44 

.44 
.45 
.45 
.48 
.53 
.62 
.64 
.65 
.65 

P.ct. 
0.54 
.51 
.46 
.48 
.53 
.54 
.56 
.56 
.58 
.60 
.59 

P.ct. 
0.53 
.52 
.51 
.54 
.55 
.55 
.55 
.57 
.63 
.70 

P.  ct. 
O.  52 
.49 
.47 
.47 
.49 
.51 
.53 
.57 
.58 
.60 
.64 

P.ct. 
0.53 

2 

.51 

3 

.48 

4 

.50 

5 

.52 

6 

.53 

7 

.55 

8 

•  57 

9 

•59 

10 

•63 

11 

•61 

12 

13 

:::: 

14 

True    average    of    total 

.47 
3.00 

.42 
2.70 

.50 
3.21 

.46 
2.93 

.53 
3.40 

.55 
3.49 

.31 

3.28 

•53 
3-38 

True    average    of    total 

Table  8. — Average  percentage  of  total  protein  in  milk  of  dairy  cattle,  as  reported  by 
American  experiment  stations. 


New  Jersey. 

New  York.                  Missouri. 

Average. 

Breed. 

Number 

of 
animals. 

Average 
protein. 

Number 

of 
animals. 

Average 
protein. 

Number 

of 
animals. 

Average 
protein. 

Number 

of 
animals. 

Average 
protein. 

Jersey 

3 
3 
3 
3 
3 

Per  cent. 
3.96 
3.92 
3.48 
3.28 
3.27 

3 

2 
4 
2 

Per  cent. 
3.81 
3.75 
3.29 
3.23 

3 

Per  cent. 
3.64 

9 
5 
9 
8 
6 

Per  cent. 
3.80 

Guernsey 

3.84 

Ayrshire 

2 
3 

3 

3.25 
2.93 
3.38 

3.34 

Holstein 

3.15 

Shorthorn 

3.32 

CASEIN. 

Table  9  gives  the  average  percentage  of  protein  in  the  form  of 
casein  for  each  individual  and  for  each  breed.  Much  the  same  range 
of  variation  is  found  here  as  is  the  case  with  the  total  protein.  The 
percentage  of  the  total  protein  present  as  casein  was  for  the  Holstein 
milk  80.4,  the  Jersey  80.7,  the  Ayrshire  83,  and  the  Shorthorn  83.5. 
No  special  breed  characteristics  can  be  observed  in  regard  to  fche 
relation  of  casein  to  the  total  protein.  The  individual  variation  is 
of  some  importance,  but  not  so  very  much. 


16 


INFLUENCE   OF  BREED  AND   INDIVIDUALITY   ON   MILK. 


Table  9. — Average  casein  nitrogen  for  each  cow,  and  breed  average,  by  J^-week  periods 
and  average  casein  nitrogen  and  casein  for  the  whole  lactation  period. 


Four-week  period  No. 

Jerseys. 

Ayrshires. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

Per  cent. 
0.44 
.38 
.48 
.49 
.48 
.48 
.47 
.46 
.50 
.52 

Per  cent. 
0.42 
.41 
.40 
.40 
.40 
.40 
.39 
.40 
.42 
.46 
.51 
.53 

Per  cent. 

Per  cent. 
0.43 
.37 
.45 
.44 
.47 
.47 
.47 
.47 
.48 
.49 
.51 
.54 
.61 
.58 

Per  cent. 
0.44 
.40 
.40 
.38 
.39 
.39 
.39 
.44 
.52 
.59 

Per  cent. 
0.56 
.50 
.48 
.51 
.51 
.53 
.51 
.50 
.53 
.53 
.53 
.57 
.65 

Per  cent. 
0.50 

2 

.32 

.48 
.42 
.54 
.52 
.54 
.54 
.51 
.50 
.51 
.55 
.61 
.58 

.45 

3 

.44 

4 

.45 

5 

.45 

6 

.46 

7 

.45 

8 

.47 

9 

.53 

10 

.56 

11 

.53 

12 

.57 

13 

.65 

14 

True   average   of  casein 
nitrogen 

.46 
2.93 

.42 
2.65 

.49 
3.13 

.46 
2.93 

.41 
2.62 

.44 
2.81 

.42 

True  average  of  casein 

2.70 

Four-week  period  No. 

Holsteins. 

Shorthorns. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1 

Per  ct. 
0.40 
.35 
.34 
.36 
.37 
.38 
.37 
.37 
.38 
.39 
.43 
.45 
.51 
.57 

Per  ct. 
0.34 
.30 
.29 
.30 
.32 
.33 
.31 
.33 
.36 
.42 
.58 

Per  ct. 
0.39 
.34 
.34 
.36 
.35 
.36 
.39 
.40 
.41 
.49 
.53 
.59 
.58 

Per  ct. 
0.38 
.33 
.32 
.34 
.35 
.36 
.36 
.37 
.38 
.43 
.51 
.52 
.54 
.57 

Per  ct. 
0.45 
.41 
.38 
.38 
.44 
.44 
.45 
.46 
.45 
.48 
.53 

Per  ct. 
0.44 
.43 
.42 
.44 
.45 
.44 
.45 
.45 
.53 
.56 

Per  ct. 
0.42 
.38 
.36 
.37 
.37 
.43 
.46 
.47 
.46 
.45 
.48 

Per  ct. 
0.44 

2.  .                   

.41 

3                                   

.39 

4 

.39 

5 

.42 

6  ..                            

.44 

7 

.45 

8 

.46 

9...                

.48 

10...                   

.49 

11 

.51 

12 

13 

14 

True    average    of   casein 

.39 
2.49 

.33 

2.11 

.39 
2.49 

.37 
2.36 

.43 
2.74 

.45 

2.87 

.41 
2.62 

.43 

True  average  of  casein 

2.74 

RELATION    OF    THE    CASEIN    TO   THE    FAT. 

The  relation  between  the  fat  and  the  casein  is  of  considerable 
interest  on  account  of  the  possibility  it  affords  of  calculating  the 
casein  content  from  the  fat  analyses  and  its  relation  to  methods  of 
paying  for  milk  of  varying  quality  to  be  used  for  cheese  making. 
Van  Slyke  *  formulated  a  rule  for  estimating  the  casein,  limited  in 
its  application  to  milk  with  fat  contents  between  3  and  4.5  per  cent. 
Shuttleworth  2  showed  that  considerable  variations  occur  with  indi- 
vidual cows  regarding  the  relation  of  fat  to  casein. 

i  Van  Slyke,  Lucius  L.  Modern  methods  of  testing  milk  and  milk  products.  New  York,  1907.  See 
p.  192. 

a  Ontario  Agricultural  College  and  Experimental  Farm,  Twenty-first  Annual  Report  (1895),  pp.  19-27. 
Toronto,  1896. 


RESULTS   OF   THE   EXPERIMENTS. 


17 


Hart  '  studied  the  relation  between  the  fat  and  the  casein  in  the 
milk  of  26  cows  representing  5  breeds  and  covering  12  days'  time. 
He  finds  that  "the  relation  of  casein  to  fat  varies  among  animals  of 
different  breeds  and  among  animals  of  the  same  breed."  His  data 
averaged  by  breeds  are  as  follows: 


Breed. 


Relation 

of  fat  and 

casein. 


Jersey... 
Guernsey 
Holstein. 

Ayrshire. 


1.72:1 
1.90:1 
1.49:1 
1.44:1 


The  following  gives  the  relation  of  the  fat  to  the  casein  in  the  milk 


of  each  of  the  11  cows  used  in  our  investigation 


Breed. 

No. 

•  Ratio  of 
fat  to 
casein. 

Jersey 

4 

99 
118 

1.66:1 
1.75:1 
1.71  : 1 

Do 

Do 

Average  for  Jerseys 

1.69:1 

Ayrshire 

300 

301 

1.20:1 
1.47:1 

Do 

Average  for  Avrshires 

1.36:1 

Holstein 

205 
206 
209 

1.30:1 
1.38:1 
1.25:1 

Do 

Do 

Average  for  Holsteins 

1.31  :1 

Shorthorn 

400 
402 
403 

1.35:1 
1.44:1 
1.29:1 

Do... 

Do 

Average  for  Shorthorns . . . 

1.36:1 

The  above  statement,  representing  as  it  does  in  each  case  the 
entire  lactation  period  of  the  animal  fed  a  uniform  ration,  gives  a 
fair  basis  from  which  to  study  this  question.  The  figures  show  that 
there  is  a  variation  in  the  ratio  between  the  fat  and  the  casein  that  is 
dependent  upon  breed.  There  is  little  difference  between  the 
Holstein,  Ayrshire,  and  Shorthorn  breeds,  but  the  Jersey  shows  a 
much  wider  ratio  than  the  others.  A  study  of  the  figures  for 
the  individual  animals  shows  a  reasonably  close  agreement  within 
the  breed.  The  conclusion  from  our  data  would  be  that  while  there 
is  some  variation  with  the  individual  the  variation  due  to  breed  is  of 
greater  importance,  and  that  the  breeds  that  have  the  highest  per- 
centage of  fat  have  the  widest  ratio  between  the  fat  and  the  casein. 


i  Hart,  E.  B.    Variations  in  the  amount  of  casein  in  cow's  milk. 
Society,  vol.  30,  No.  2,  pp.  281-285.    Easton,  Pa.,  Feb..  1908. 


Journal  of  the  American  Chemical 


18 


INFLUENCE   OF  BREED  AND   INDIVIDUALITY    ON    MILK. 


SUGAR. 

The  sugar  content  was  determined  by  the  optical  method.1  The 
results  are  found  in  Table  10.  This  table  shows  that  the  percentage 
of  sugar  in  the  milk  of  the  Jersey,  Ayrshire,  and  Shorthorn  breeds  was 
practically  the  same,  while  that  in  the  Holstein  was  somewhat  lower. 

Table  11  gives  the  average  percentage  of  sugar  from  the  same 
sources  as  previously  used.  The  average  figures  show  that  the 
Holstein  breed  has  a  somewhat  lower  percentage  of  sugar  than  the 
other  breeds,  although  the  variation  is  small  as  compared  with  that 
of  other  constituents.  It  is  a  well-established  fact  that,  with  the 
exception  of  the  ash,  sugar  is  the  least  subject  to  variations  of  the 
milk  constituents.  Some  variation,  however,  is  found  with  the 
individuals.  This  is  especially  noticeable  with  the  Holsteins,  where 
one  has  an  average  of  5.05  per  cent  and  another  4.25  per  cent.  The 
sugar  composes  from  34  to  39  per  cent  of  the  total  solids,  varying  in 
this  respect  with  the  breed. 
Table  10.— Average  percentage  of  sugar  for  each  cow,  and  breed  average,  by  4-weeh  periods. 


Jerseys. 

Ayrshires. 

Four-week  period  No. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

Per  cent. 
4.89 
4.99 
4.87 
5.28 
5.12 
5.00 
4.39 
4.45 
4.67 
4.60 

Per  cent. 
4.94 
5.15 
5.17 
5.06 
5.04 
4.50 
4.52 
5.14 
4.62 
5.03 
5.02 
5.61 

Per  cent. 

Per  cent. 
4.92 
4.87 
4.91 
4.97 
4.99 
4.90 
4.70 
4.99 
4.62 
4.79 
4.96 
5.17 
4.46 
5.22 

Per  cent. 
5.14 
4.81 
4.64 
4.87 
4.96 
4.57 
4.82 
5.08 
5.13 
4.39 

Per  cent. 
5.17 
4.72 
5.62 
5.16 
4.77 
4.43 
5.38 
5.13 
4.85 
4.88 
4.89 
5.04 
5.13 

Per  cent. 
5.16 

2 

4.47 
4.70 
4.56 
4.83 
5.21 
5.20 
5.40 
4.57 
4.73 
4.90 
4.72 
4.46 
5.22 

4.77 

3 

4 

5.13 
5.02 

5 

4.87 

6  

4.50 

7 

5.10 

8 

5.11 

9 

4.99 

10 

4.64 

U 

4.89 

12 

5.04 

13 

5.13 

14 

True  total  average 

4.85 

4.95 

4.80 

4.87 

4.85 

4.96 

4.90 

Holsteins. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1 

Per  ct. 
4.69 
4.98 
4.84 
5.18 
5.42 
5.37 
5.20 
4.76 
5.10 
5.12 
5.13 
5.02 
4.89 
4.81 

Per  ct. 
4.07 
4.49 
4.44 
4.12 
4.26 
4.04 
4.74 
4.25 
4.09 
3.94 
4.50 

Per  ct. 
4.40 
4.00 
4.17 
3.95 
4.42 
4.36 
4.16 
3.94 
4.43 
4.62 
4.79 
4.15 
4.30 

Per  ct. 
4.39 
4.49 
4.48 
4.42 
4.70 
4.59 
4.70 
4.32 
4.54 
4.56 
4.81 
4.64 
4.60 
4.81 

Per  ct. 
5.40 
5.06 
5.44 
5.13 
4.87 
4.95 
5.05 
5.19 
4.65 
4.22 
4.25 

Per  ct. 
4.77 
5.32 
5.09 
4.72 
4.55 
5.09 
5.29 
4.73 
4.61 
4.31 

Per  ct. 
5.21 
5.22 
5.39 
5.00 
4.58 
5.16 
4.98 
5.11 
4.08 
4.17 

Per  ct. 
5.13 

2 

5.20 

3 

5.31 

4 

4.95 

5 

4.67 

6 

5.07 

7 

5.11 

8 

5.01 

9 

4.45 

10... 

4.23 

11 

4.25 

12 

13 

14 

True  total  average 

5.05 

4.26 

4.25 

4.51 

5.04 

4.91 

4.98 

4.99 

1  Official  and  provisional  methods  of  analysis.     U.  S.  Department  of  Agriculture,  Bureau  of  Chemistry, 
Bulletin  107  (revised).    Washington,  1908.    Seep.  118. 


RESULTS    OF    THE    EXPERIMENTS 


19 


Table  11.—  Average  percentage  of  sugar  in  milk  of  dairy  cattle,  as  reported  by  Arherican 

experiment  stations. 


New  Jersey.                 New  York. 

Missouri.                     Average. 

Breed. 

Number 

of 
animals. 

Average 
sugar. 

Number 

of 
animals. 

Average 
sugar. 

NuSbCT    Average 
animals.      suSar- 

Number 

of 
animals. 

Average 
sugar. 

3 
3 
3 
3 
*       3 

Per  cent. 
4.85 
4.80 
4.84 
4.69 
4.80 

3 
2 
4 
2 

Per  cent. 
5.41 
5.16 
5.33 
5.02 

3 

Per  cent. 
4.87 

9 
5 
9 
6 
6 

Per  cent. 
5.04 

4.98 

2 
3 
3 

4.90 
4.25 
4.99 

5.02 

Holstein. . . 

4.65 

Shorthorn 

4.89 

THE    CHEMICAL   AND    PHYSICAL    CONSTANTS    OF    THE    FAT. 

While  the  previously  published  data  regarding  the  constituents  of 
milk  are  extensive,  little  is  in  print  concerning  the  chemical  and  physi- 
cal constants  of  the  fat  as  influenced  by  the  breed  and  individuality  of 
the  animal,  with  the  exception  of  the  relative  size  of  the  fat  globules. 
Veith 1  studied  the  milk  of  3  breeds  of  cows  and  concluded  that  the 
breed  does  not  have  any  appreciable  influence  upon  the  nature  of  the 
fat.  Kirchner2  states  that  the  composition  of  the  fat  is  dependent 
mostly  upon  the  stage  of  lactation  and  the  food  of  the  animal,  but  also 
varies  to  some  extent  with  the  individual  animal. 

The  object  of  the  investigations  herein  reported,  as  far  as  the  varia- 
tions due  to  breed  and  individuality  are  concerned,  was  especially  to 
gather  data  concerning  the  fat.  Since  the  rations  fed  the  animals  was 
uniform  in  all  cases,  the  variations  found  can  reasonably  be  attributed 
to  the  influence  of  the  breed  or  of  the  individual. 

RELATIVE    SIZE    OF    THE    FAT    GLOBULES. 

The  determination  of  the  relative  size  of  fat  globules  was  introduced 
by  Babcock.3  A  description  of  this  method  of  measurement  is  also 
found  in  Bulletin  111,  Bureau  of  Animal  Industry,  United  States 
Department  of  Agriculture.  The  method  is  essentially  one  of  com- 
paring the  average  volumes.  It  has  been  observed  by  several  inves- 
tigators that  the  breed  of  the  animal  has  a  decided  influence  upon  the 
size  of  the  fat  globules.  Jones 4  found  that  the  milk  of  the  Holstein 
had  a  much  larger  proportion  of  small  fat  globules,  while  the  Jersey 
and  the  Guernsey  had  the  largest,  the  Ayrshire  standing  between. 
Woll5  gives  the  following  data  concerning  the  size  of  the  fat  globules 

» Vieth,  P.  Butterfett-Untersuchungen  nach  Reichert-Wollny's  Methode.  Milch  Zeitung.  vol.  18,  no. 
28,  p.  541-545.    Bremen,  July  10, 1889. 

2  Kirchner,  W.    Handbuch  der  Milchwirtschaft.    Berlin,  1898.    See  p.  16. 

3New  York  Agricultural  Experiment  Station,  Fourth  Annual  Report  (1885),  p.  293-302.    Albany ,  1886. 

4  Jones,  L.  R.  Study  of  milk  globules.  Vermont  Agricultural  Experiment  Station,  Fourth  Annual 
Report  (1890),  p.  65-69.    Burlington,  1891. 

s  Woll,  F.  W.  The  fat  globules  in  cows'  milk.  Wisconsin  Agricultural  Experiment  Station,  Eleventh 
Annual  Report  (1894),  p.  223-239.    Madison,  1895. 


20 


INFLUENCE   OF  BREED  AND   INDIVIDUALITY   ON   MILK. 


in  the  milk  of  the  3  breeds  which  were  entered  in  competition  at  the 
Columbian  Exposition  at  Chicago  in  1893: 


Breed. 

Number 
of  cows. 

Relative 

size  of 

globules. 

Average 
diameter. 

25 
25 
24 

290 
217 
177 

Microns. 
3.95 
3.58 
3.35 

Guernsey 

Shorthorn 

Gutzeit 1  gives  the  average  diameter  of  the  fat  globules  in  his  inves- 
tigation as  follows : 

Microns. 

Jersey 3.  50 

Shorthorn 2.  76 

Holstein 2.  58 

Table  12  gives  the  relative  size  of  the  fat  globules  as  determined  for 
each  of  the  1 1  animals  used  in  our  investigation  and  the  averages  for 
the  breeds.  This  table  shows  the  same  results  as  noted  by  others,  the 
Jersey  having  by  far  the  largest  fat  globules,  while  the  Holstein  have 
the  smallest,  the  Shorthorn  standing  between  the  Holstein  and  the 
Jersey.  The  comparative  size  of  the  fat  globules  in  the  milk  of  these 
4  breeds  is  illustrated  graphically  in  figure  1.     The  chief  difference 


AYRSHIRE  HOLSTEIN 

JERSEY  SHORTHORN 

Fig.  1.— Relative  size  of  the  fat  globules  in  the  milk  of  dairy  cattle. 

between  the  size  of  the  fat  globules  with  the  different  breeds  is  that 
with  the  Jersey  there  is  a  greater  proportion  of  the  larger  globules  and 
that  the  milk  of  the  other  breeds  contains  a  limited  number  as  large 
as  the  largest  in  the  Jersey  milk.  The  milk  of  the  Holstein  breed  is 
especially  noticeable  in  containing  a  large  number  of  small  fat  globules, 
together  with  a  wide  variation  in  size. 

The  table  shows  that  the  individuality  of  the  animal  has  some  influ- 
ence upon  the  size  of  the  fat  globules,  but  it  is  of  less  importance  than 
the  breed  characteristic.  The  milk  of  an  Ayrshire  or  a  Holstein  can 
be  distinguished  from  that  of  a  Jersey  with  considerable  certainty  by 
the  characteristic  of  the  fat  globules  alone.     The  Shorthorn,  on  the 

1  Gutzeit,  Ernst.  Die  Schwankungen  der  mittleren  Grosse  der  Fettkiigelchen  in  der  Kuhmilch  nach 
Laktation,  Futterung  und  Rasse,  sowie  iiber  den  physikalischen  und  chemischen  Unterschied  der 
grossten  und  kleinsten  Fettkiigelchen.  Landwirthschaftliche  Jahrbiicher,  vol.  24,  p.  539-667.  Berlin, 
1895.    See  p.  648. 


RESULTS   OF    THE   EXPERIMENTS. 


21 


other  hand,  has  fat  globules  that  in  many  cases  are  as  large  as  those 
contained  in  the  milk  of  the  Jersey,  although  less  uniform  in  size. 

Table  12. — Relative  size  of  fat  globules  in  milk  of  each  cow,  and  breed  average,  by  4-week 

periods. 


Four  week  period  No. 

Jerseys. 

Ayrshlres. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1      

363 

423 
370 
229 
267 
267 
235 
299 
318 
228 
167 

556 
339 
325 
274 
264 
349 
370 
367 
270 
209 
263 
315 

459 
381 
371 
461 
296 
326 
302 
333 
308 
232 
257 
272 
438 
461 

235 
163 
148 
135 
115 
133 
93 
80 
75 
129 

232 
189 
142 
155 
165 
178 
163 
151 
146 
114 
146 
93 
110 

234 

2          

176 

3 

417 
879 
3.58 
373 
301 
334 
335 
259 
342 
229 
438 
461 

145 

4.. 

145 

140 

6 

156 

128 

8 

116 

9 

'ill 

10 

122 

11.. 

146 

12.. 

93 

13 

110 

14.. 

True  average  of  relative 

309 

330 

338 

328 

- 

160 

150 

Holsteins. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1 

242 

147 

148 

147 

127 

82 

107 

96 

98 

90 

81 

117 

102 

179 

253 

269 

124 

157 

134 

155 

132 

110 

96 

74 

79 

321 

139 

136 

138 

104 

89 

98 

99 

105 

79 

63 

76 

118 

272 
185 
136 
147 
122 
109 
112 
102 
99 
81 
74 
97 
110 
179 

442 
593 
317 
245 
250 
277 
231 
197 
214 
179 
194 

566 
561 
394 
274 
280 
232 
271 
214 
213 
193 

357 
303 
213 
183 
134 
141 
146 
147 
203 
175 
128 

455 

2 

486 

3 

308 

4 

234 

5 

221 

6 

217 

7 

216 

8 

186 

9 

210 

10 

182 

11 

161 

12 

13 

14 

■  1 

True  average  of  relative 
size  of  globules 

127 

164 

134 

142 

311 

353 

211 

282 

THE    REICHERT-MEISSL    NUMBER.1 

The  results  for  the  Reichert-Meissl  number  are  given  in  Table  13. 
The  Holsteins  show  the  lowest  figure  for  the  number,  although  the 

1  This  and  the  two  succeeding  constants  of  the  fat  were  determined  by  official  methods,  the  details  of 
which  may  be  found  in  Bulletin  107  (revised),  Bureau  of  Chemistry,  U.  S.  Department  of  Agriculture. 
For  the  benefit  of  those  who  may  be  unfamiliar  with  the  terms  the  following  explanation  may  be  helpful: 
The  Reichert-Meissl  number  is  an  arbitrary  measure  of  the  volatile  acids  of  which  butyric  is  the  principal 
one  in  butterfat.  The  figures  do  not  show  the  percentages  of  the  acid,  but  serve  as  a  means  of  comparing 
different  fats  with  reference  to  their  volatile  constituents.  The  iodin  absorption  number  indicates  rela. 
tively  the  amount  of  iodin  a  fat  will  absorb.  Since  the  only  fatty  acid  found  to  exist  in  butterfat  which 
has  the  property  of  absorbing  iodin  is  oleic  acid,  the  iodin  absorption  number  shows  relatively  the  amount 
of  this  fatty  acid  present,  but  in  common  with  the  Reichert-Meissl  number  the  figures  do  not  represent 
percentages.  The  saponification  number  is  the  number  of  milligrams  of  potassium  hydroxid  required 
to  saponify  1  gram  of  fat.  Since  the  amount  of  potassium  hydroxid  required  depends  upon  the  molecular 
weight  of  the  fat  the  saponification  number  serves  as  an  indicator  of  the  relative  percentages  of  the  fatty 
acids  of  high  and  low  molecular  weights  present. 


22 


INFLUENCE  OF  BREED  AND   INDIVIDUALITY   ON   MILK. 


Ayrsbires  on  the  average  are  only  0.5  higher,  while  the  Shorthorns 
and  the  Jerseys  show  a  somewhat  higher  figure.  The  individual 
variations  are  very  marked  in  the  case  of  Jersey  No.  118  with  an 
average  of  23.28,  which  is  the  lowest  of  the  entire  number.  If  the 
data  of  this  individual  was  not  included  the  average  for  the  Jersey 
would  be  considerably  higher  than  any  of  the  other  breeds.  With 
the  exception  of  this  individual  there  is  no  marked  variation  that  is 
to  be  attributed  to  the  individuality  of  the  animal.  The  marked 
variation  in  the  Reichert-Meissl  number  due  to  the  advance  in  the 
period  of  lactation  is  evident  from  the  table. 

Table  13. — Average  Reichert-Meissl  number  for  each  coiv,  and  breed  average,  by  4-week 

periods. 


Four-week  period  No. 

Jerseys. 

Ayrshires. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1 

29.22 

28.72 
28.52 
28.50 
28.96 
29.20 
26.87 
28.63 
25.24 
25.95 

30.16 

28.88 
32.09 
30. 95 
27.67 
31.21 
27.03 
27.54 
27.03 
25.83 
24.73 
18.43 

29.54 
23.28 
24.14 
23.69 
23.90 
24.64 
26.66 
23.12 
25.04 
22  85 
22.79 
20.22 
14.23 
14.21 

29.64 
26.96 
28.25 
27.71 
26.84 
28.35 
26.83 
29.76 
25  77 
24.88 
23.76 
19  33 
14.23 
14.21 

27.66 
28.96 
27.76 
25.76 
26.83 
25.76 
24.57 
23.87 
23.09 
17.96 

30.59 
27.09 
26.58 
25.13 
24.88 
26.79 
25.59 
26.40 
24.42 
24.36 
18.09 
21.72 
20.67 

29.13 

2 

28.03 

3 

27.17 

4   

25.45 

5 

25.86 

6 

26.28 

7 

25.08 

8      

25.29 

9 

23.76 

10 

21.16 

11             

18.09 

12 

21.72 

13 

20.67 

14 - 

True  average  of  Reichert- 
Meissl  number 

28.17 

28.69 

23.28 

26.73 

26.34 

25.52 

25.93 

Holsteins. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1     

26.66 
26.01 
26.33 
27.38 
27.82 
26.92 
28.05 
27.53 
27.86 
26.06 
25.63 
20.39 
12.77 
10.  27 

30.15 
29.48 
28.15 
24.58 
27.19 
24.51 
24.28 
23.39 
23.53 
20.  76 
17.62 

25.65 
26.84 
25.10 
27.05 
24.82 
24.68 
22.79 
23.47 
24.23 
20. 17 
21.32 
20.70 
21.14 

27.49 
27.44 
26.53 
26.34 
26.61 
25.37 
25.04 
24.80 
25.21 
22. 33 
21.52 
20.55 
16.96 
10.27 

30.77 
29.31 
25.95 
25.99 
28.58 
26.54 
24.70 
25.99 
24.46 
22.57 
22.25 

30.72 
27.14 
26.69 
25.60 
26.07 
24.12 
23.75 
22.93 
18.39 
16.61 

29.36 
26.67 
26.31 
26.30 
25.69 
26.02 
26.38 
24.53 
23.27 
24.25 
25.51 

30.28 

2 

27.71 

3 

26.32 

4 

25.96 

5 

26.78 

6 

25.56 

7 

24.94 

8 

24.48 

9 

22.04 

10 

21.14 

11 

23.88 

12 

13.. 

14 

True  average  of  Reichert- 
Meissl  number 

25.81 

26.13 

24.44 

25.46 

26.89 

25.55 

26.29 

26.28 

KESULTS   OF  THE   EXPERIMENTS. 


23 


THE   IODIN   ABSORPTION   NUMBER. 

Table  14  gives  the  data  in  regard  to  the  iodin  number  for  each 
individual  and  for  the  4  breeds.  It  will  be  observed  that  with  this 
constant  there  is  an  evident  variation  due  to  breed.  The  Shorthorn 
and  the  Holstein  show  a  noticeably  higher  iodin  number  than  the 
Jersey,  while  the  Ayrshire  comes  between.  The  Jersey  cow  No.  118 
shows  an  individual  variation  in  this  respect,  as  is  the  case  with  the 
Reichert-Meissl  number.  If  the  figures  on  this  animal  be  left  out  of 
the  total  the  variation  with  the  breeds  would  be  even  more  marked. 
The  variation  with  the  breeds,  since  it  shows  practically  the  same  for 
each  individual,  seems  sufficient  to  warrant  the  conclusion  that  there 
is  a  variation  in  this  constant  to  be  attributed  to  breed  and  that  the 
Holstein  and  the  Shorthorn  may  be  expected  to  show  the  highest 
figures,  while  the  Jersey  is  at  the  other  extreme. 

Table  14. — Average  iodin  number  for  each  cow,  and  breed  average,  by  4-week  periods. 


Jerseys. 

Ayrshires. 

Four-week  period  No. 

No.  4. 

No.  99.      No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

, 

31.08 
28.04 
29.61 
29.94 
28.84 
28.03 
31.46 
29.75 
32.  27 
32.15 

32.68 
29.46 
28.96 
26.75 
29.99 
27.29 
27.93 
27.37 
28.71 
28.80 
27.61 
29.55 

39  31 
36.33 
32.54 
28.69 
31.55 
30.  43 
28.67 
32.49 
33.67 
31.43 
31.14 
32.37 
38.48 

34.36 
31.28 
30.37 
28.46 
30.13 
28.58 
29.35 
29.87 
31.55 
30.79 
29.38 
30.96 
38.48 
35.82 

32.58 
28.70 
27.69 
31.91 
27.50 
29.61 
35.30 
37.32 
35.23 
37.74 

28.58 
29.91 
30.56 
29.85 
30.93 
30.31 
31.04 
30.54 
32.64 
35.11 
44.11 
39.62 
36.80 

30.53 

2 

29.31 

3 

29.13 

4 

30.88 

5 

29.22 

6 

7 

29. 96 
33.17 

8 

33.93 

9 

33.94 

10 

36.43 

11.. 

44.11 

12 

39.62 

13 

36.80 

14 

35.82 

True  total  average 

29.99 

28.87           32.79 

30.52 

31.14 

32.06 

31.61 

Four-week  period  No. 

Holsteins. 

Shorthorns. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

Average 
No.  403.  for  Short- 
horns. 

1 

37.12 
34.  .54 
33.23 
31.85 
31.77 
32.64 
32.62 
33.45 
34.07 
35.55 
35.40 
37.53 
42.57 
42.24 

31.00 
30.57 
35.53 
31.70 
31.79 
31.67 
33.14 
34.25 
33.91 
35.27 
36.53 

39.46 
33.  32 
32.89 
33.10 
33.53 
34.91 
35.62 
35.59 
37.01 
39.08 
35.35 
36.69 
39.03 

35.86 
32.81 
33.88 
32.22 
32.36 
33.07 
34.13 
34.43 
35.00 
36.63 
35.76 
37.11 
40.80 
42.24 

30.13 
32.12 
39.05 
31.36 
31.66 
33.31 
35.71 
33.25 
34.28 
36.91 
38.49 

30.76 
39.21 
31.15 
30.42 
32.08 
35.16 
35.13 
35.47 
41.01 
42.19 

33.33 
35.18 
33.19 
33.75 
35.28 
35.  57 
34.96 
36.34 
37.32 
35.24 
35.04 

31.42 

2 

35.50 

3 

34.46 

4 

31.84 

5 

33.01 

6 

34.68 

7 

35.  26 

8 

35.02 

9 

37.54 

10 

38.11 

11 

3&  77 

12 

13 

14 

True  total  average 

34.46 

32.68 

35.48 

34.20 

34.08 

34.09 

34.72 

34.36 

24 


INFLUENCE   OF   BEEED  AND   INDIVIDUALITY   ON   MILK. 


THE    SAPONIFICATION    OR   KOETTSTORFER   NUMBER. 

The  data  regarding  this  constant  are  found  in  Table  15.  The  varia- 
tions that  may  be  attributed  to  breed  are  comparatively  small.  The 
Holsteins  show  a  number  1.5  higher  than  the  Shorthorns.  This  dif- 
ference, while  comparatively  small,  seems  to  indicate  at  least  some 
tendency  for  a  variation  between  these  two  breeds.  With  this  excep- 
tion no  special  variation  can  be  observed  that  may  be  attributed 
safely  to  the  influence  of  the  breed.  No  marked  individual  varia- 
tions are  observed,  with  the  exception  of  Jersey  cow  No.  118,  which 
shows  individual  variations  in  this  as  well  as  in  the  other  constants. 
A  high  iodin  number  is  usually  associated  with  a  low  Reichert-Meissl 
number  and  a  low  saponification  number.  The  data  of  cow  No.  118 
follow  this  rule.  The  variations,  however,  are  not  sufficient  to  justify 
any  special  emphasis  being  placed  upon  either  breed  or  individuality 
as  a  factor  in  causing  variations  in  the  saponification  number. 

Table  15. — Average  saponification  number  for  each  cow,  and  breed  average,  by  4-week 

periods. 


Jerseys. 

Ayrshires. 

lour-week  period  No. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
lor  Ayr- 
shire's. 

1 

231.1 
233.1 
232.9 
229.1 
230.7 
229.0 
227.8 
229.4 
234.4 
235.9 

230.6 
232.1 
229.5 
232.3 
227.7 
231.7 
227.3 
239.8 
234.3 
231.4 
229.4 
219.6 

228.5 
224.7 
229.6 
229.0 
230.2 
226.6 
229.4 
224.8 
225.1 
227.6 
237.0 
223.9 
219.5 
219.1 

230.1 
229.9 
230.7 
230.1 
229.5 
229.1 
228.2 
231.3 
231.3 
231.6 
233.2 
221.8 
219  5 
219.1 

232.6 
230.7 
^32.3 
224.8 
229.2 
230.1 
224.5 
222.0 
223.9 
217.2 

236.9 
234.1 
232.0 
230.4 
227.5 
229.7 
219.6 
228.3 
228.4 
224.3 
216.2 
218.7 
221.3 

234.7 

2 

232.4 

3 

232.1 

4        

227.6 

5                 

228.4 

G                          

229.9 

7                          

222.0 

8 

225.1 

9 

226.1 

10 

220.8 

11 

216.2 

12                   

218.7 

13 

221.3 

14 

True  total  average 

231.3 

228.6 

227.2 

228.9 

228.4 

227.9 

228.2 

Holsteins. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206. 

No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1                 

242.2 
229.3 
229.0 
232.9 
230.  8 
228.7 
228.1 
227.0 
225.0 
223.  9 
226.3 
220.8 
210.1 
205.9 

230.7 
228.3 
242.4 
233.7 
232.4 
231.2 
229.7 
225.6 
224.4 
219.9 
216.4 

237.2 
230.6 
231.6 
230.8 
228.3 
229.0 
224.0 
222.4 
222.0 
219.2 
222.0 
230.3 
215.3 

233.4 
229.4 
234.3 
232.8 
230.5 
229.6 
227.3 
225.0 
223.8 
221.0 
221.6 
225.5 
212.7 
205.9 

232.3 
231.7 
224.2 
230.0 
229.4 
227'.  2 
223.9 
226.5 
224.9 
220.5 
216.8 

234.3 
233.9 
229.8 
223.0 
228.3 
224.3 
223.7 
222.7 
215.8 
211.5 

234.3 
225.4 
228.1 
229.9 
226.4 
230.1 
224.6 
225.  1 
223.8 
226.4 
226.6 

233.6 

2                         

230.3 

3                             

227.4 

4...           

227.6 

5...             

228.0 

6.              

227.2 

7.                  

224. 1 

8...                   

224.8 

9 

221.5 

10 

219.5 

11... 

221.7 

12 

13 

14 

True  total  average 

228.2 

230.1 

229.1 

229.1 

227.6 

226.  9 

227.9 

227.6 

RESULTS    OF    THE    EXPERIMENTS, 


25 


THE    MELTING   POINT   OF  THE   FAT. 


The  melting  point  was  determined  according  to  Wiley's  method. 
An  examination  of  the  data  given  in  Table  16  shows  a  close  agreement 
in  the  melting  point  for  all  of  the  animals.  Apparently  there  is  no 
variation  in  the  melting  point  that  could  reasonably  be  attributed 
either  to  the  breed  or  to  the  individuality  of  the  animal  supplying 
the  samples.  A  marked  variation  is  noticeable  due  to  the  advance 
in  lactation  period,  but  this  is  regardless  of  the  individual  or  breed. 

Table  17  gives  a  summary  for  comparison  of  the  constants  of  the 
fat  for  the  four  breeds. 


Table  16. — Average  melting  point  of  the  fat  for  each  cow,  and  breed  average,  by  4-week 

-periods. 


Jerseys. 

Ayrshires. 

Four-week  period  No. 

No.  4. 

No.  99. 

No.  118. 

Average 

for 
Jerseys. 

No.  300. 

No.  301. 

Average 
for  Ayr- 
shires. 

1 

"C. 

32.36 
32.63 
33.39 
32. 25 
33.30 
33.44 
32.94 
33.24 
33. 03 
32.97 

°a 

24.94 
33.24 
33.36 
34.53 
33.78 
34.08 
34.07 
34.33 
34.64 
33.81 
34.88 
34.35 

°C. 

26.62 

32.66 

33.31 

33.31 

33.80 

33.40 

33. 92 

33.66 

33.39 

33.59 

33.81 

33.68 

33.46 

33.50 

°C. 

27.97 

32.84 

33.35 

33.36 

33.63 

33.64 

33.64 

33.74 

33.69 

33.46 

34.35 

34.02 

33.46 

33.50 

°C. 

34.80 
33.39 
33.45 
33.54 
33.74 
33.87 
33.83 
33.30 
33.30 
34.04 

°C. 

32.  07 

33.21 

32.61 

32.80 

33.85 

32.98 

33.98 

33. 55 

33.33 

33. 10 

34.35 

33.23 

33.28 

°C. 
34.44 

2  

33.30 

3 

33.03 

4 

33.17 

5 

33.79 

6 

33.43 

7 

33.90 

8 

33.43 

9 

33.32 

10 

33.57 

11 

♦      34. 35 

12 

33.23 

13 

33.28 

14 

True  total  average 

32.91 

32.95 

32.99 

32.95 

33.75 

33.20 

33.47 

Hoi  steins. 

Shorthorns. 

Four-week  period  No. 

No.  205. 

No.  206.  No.  209. 

Average 

for 
Holsteins. 

No.  400. 

No.  402. 

No.  403. 

Average 
for  Short- 
horns. 

1 

°C. 
33.41 
32.67 
33. 39 
33.76 
33.02 
32.93 
32.88 
32.98 
33.26 
33.09 
33.01 
32.54 
41.80 
48.34 

°C. 
32.95 
33.52 
31.94 
32.06 
32.47 
32.47 
32.64 
33.13 
32.81 
32.92 
38.80 

°C. 
32. 58 
32.16 
32.06 
31.84 
33.04 
31.69 
32.30 
32.78 
32.85 
33.82 
33.15 
35.45 
37.39 

°a 

32.98 
32.78 
32.46 
32.55 
32.84 
32.36 
32.61 
32.96 
32.97 
33.28 
34.99 
33.99 
39.59 
48.38 

°C. 
33.91 
32.99 
31.61 
33.15 
33.01 
33.88 
33.63 
34.13 
34.21 
35.40 
36.49 

°C. 

32.69 
32.79 
33.20 
33.09 
32.95 
33.99 
33.76 
33.79 
34.65 
36.31 

°a 

32.70 
33.32 
32.70 
32.60 
33.15 
32.98 
32.54 
32.65 
33.14 
33.28 
32.83 

33.10 

2 

33.03 

3 

32. 50 

4 

32.95 

5 

33.04 

6 

32.62 

7 

33.31 

8 

33.52 

9 

34.00 

10 

34.99 

11 

34.66 

12 

13 

14 

True  total  average 

33.76 

32.87  '     32.02 

32.88 

33.56 

33.37 

32.  89 

33.23 

26  INFLUENCE   OF  BREED  AND   INDIVIDUALITY   ON   MILK. 

Table  17. — Average  chemical  and  physical  constants  of  the  fat  by  breeds. 


Breed. 

Relative 
size  of  fat 
globules. 

Iodin 
number. 

Saponifi- 
cation 
number. 

Reichert- 

Meissl 
number. 

Melting 
point. 

328 
150 
142 
282 

30.52 
31.61 
34.20 
34.36 

228.9 
228.2 
229.1 
227.6 

26.73 
25.93 
25.46 
26.28 

°C. 
32.95 

33.47 

Holstein 

32.88 

Shorthorn 

33.23 

SUMMARY    AND    CONCLUSIONS. 

1.  The  data  presented  show  the  influence  of  the  breed  and  the 
individual  upon  the  composition  of  the  milk  and  upon  the  constants 
of  the  fat  as  evidenced  by  11  cows,  including  3  each  of  the  Jersey, 
Holstein,  and  Shorthorn  breeds,  and  2  of  the  Ayrshire  breed.  These 
cows  were  kept  upon  a  uniform  ration  and  the  samples  represent  an 
entire  lactation  period  for  each.  A  compilation  is  also  given  which 
includes  all  complete  analyses  of  the  milk  of  purebred  animals  for 
entire  lactation  periods  published  up  to  the  present  by  American 
experiment  stations. 

2.  The  average  percentage  of  total  solids  is  highest  with  the  Jersey 
and  lowest  with  the  Holstein.  The  fat  represents  34.9  per  cent  of  the 
total  solids  with  the  Jersey  breed  and  28  per  cent  for  the  Holsteins. 
The  relation  of  the  fat  to  the  total  solids  is  influenced  by  breed  espe- 
cially and  to  some  extent  by  the  individual  in  the  breed. 

3.  The  data  corroborate  the  well-known  facts  regarding  the 
variations  in  fat  content  due  to  breed. 

4.  The  breed  exerts  a  decided  influence  upon  the  protein  content. 
A  low  average  percentage  of  fat  goes  with  a  low  protein  content, 
although  the  ration  is  not  constant.  Breeds  such  as  the  Jersey, 
having  a  high  fat  content  in  the  milk,  also  have  a  high  protein  con- 
tent; they  also  have  a  higher  ratio  of  fat  to  protein. 

5.  The  proportion  of  the  total  protein  present  as  casein  does  not 
seem  to  bear  any  special  relation  to  the  breed,  although  some  indi- 
vidual variations  are  observed. 

6.  The  ratio  of  casein  to  the  fat  varies  uniformly  with  the  breed. 
The  variation  between  the  Ayrshire,  Shorthorn,  and  Holstein  is  slight, 
but  the  Jersey  has  more  fat  in  proportion  to  the  casein. 

7.  The  sugar  content  of  milk  does  not  show  much  variation  either 
with  the  breed  or  with  the  individual.  Our  data  showed  a  somewhat 
lower  figure  for  the  Holsteins  than  for  the  Ayrshires,  Shorthorns,  or 
Jerseys. 

8.  The  data  presented  show  the  well-known  breed  characteristics 
regarding  the  size  of  the  fat  globules,  those  in  the  Jersey  being  the 
largest,  followed  in  order  by  the  Shorthorn,  Ayrshire,  and  Holstein. 


SUMMARY   AND   CONCLUSIONS.  27 

9.  The  breed  apparently  is  a  factor  having  some  influence  on  the 
Reichert-Meissl  number.  The  highest  was  found  with  the  Jersey, 
while  the  Holsteins  had  somewhat  lower  figures. 

10.  The  influence  of  the  breed  is  shown  on  the  iodin  number.  The 
Holsteins  and  Shorthorns  have  a  noticeably  higher  number  than 
the  Jersey,  with  the  Ayrshire  coming  between, 

11.  Little  influence  due  to  breed  or  individuality  can  be  observed 
with  the  saponification  number. 

12.  The  melting  point  of  the  fat  shows  no  variation  that  may  be 
attributed  to  breed  and  but  little  with  the  individual  animals. 

13.  With  the  exception  of  the  size  of  the  fat  globules,  the  fat  con- 
stants are  far  less  influenced  by  the  breed  and  the  individuality  of  the 
animals  than  by  the  stage  of  the  lactation  period.  The  feed  of  the 
animal  is  probably  a  greater  factor  than  breed  or  individuality  in 
influencing  the  nature  of  the  fat. 


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UNIVERSITY  OF  FLORin* 

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